I am very skeptical that File::Find will do what you think it does.
I figure that the preprocess routine will be run on each directory that is visited.
This preprocess routine will not limit the subdirs that will be visited.
This just organizes the order that files will be processed in current directory.
There are other File::Find type of modules which limit the "depth". Is that
what you want to do?
On the other hand, if you don't want to follow into other directories, why do you even need File::Find?